Influence of the Moho surface distribution on the oil and gas basins in China seas and adjacent areas

Owing to the strategic significance of national oil and gas resources,their exploration and production must be prioritized in China.Oil and gas resources are closely related to deep crustal structures,and Moho characteristics influence oil and gas distribution.Therefore,it is important to study the relationship between the variation of the Moho surface depth undulation and hydrocarbon basins for the future prediction of their locations.The Moho depth in the study area can be inverted using the Moho depth control information,the Moho gravity anomaly,and the variable density distribution calculated by the infinite plate.Based on these results,the influences of Moho characteristics on petroleum basins were studied.We found that the Moho surface depth undulation deviation and crustal thickness undulation deviation in the hydrocarbon-rich basins are large,and the horizontal gradient deviation of the Moho surface shows a positive linear relationship with oil and gas resources in the basin.The oil-bearing mechanism of the Moho basin is further discussed herein.The Moho uplift area and the slope zone correspond to the distribution of oil and gas fields.The tensile stress produced by the Moho uplift can form tensile fractures or cause tensile fractures on the surface,further developing into a fault or depression basin that receives deposits.The organic matter can become oil and natural gas under suitable chemical and structural conditions.Under the action of groundwater or other dynamic forces,oil and natural gas are gradually transported to the uplift or the buried hill in the depression zone,and oil and gas fields are formed under the condition of good caprock.The research results can provide new insights into the relationship between deep structures and oil and gas basins as well as assist in the strategic planning of oil and gas exploration activities.

THE UPWARPING AND DOWNWARPING STRUCTURAL SYSTEM OF MOHO—SURFACE IN CHINESE AND NEAR REGION AND THE GENETIC MECHANICS OF QINGHAI—TIBET PLATEAU TECTONIC

Recently, this study group established “the map of MOHO\|surface bathymetric line in Chinese and Near Region" on the basis of latest survey and study of the crustal depth, the preliminary result shows that the regular meridional and latitudinal upwarping and downwarping structural pattern of MOHO\|surface bathymetric line among Eurasian plate and Pacific plate and the Indian plate alternately appears, and which is accreted and coupled with basin ridge structure that exist shallow crustal base, continental crust and oceanic crust and others regular upwarping and downwarping net structure system that possessing different block characters and different scales exist together. Among different structure systems, it occurs that ramp downwarping impetus transform structure belts whose trends is characteristic. Nowadays upwarping and downwarping net structure system is basically modeled in Himalayan orogeny period. It is showed that the Earth revolution way has been changed in this period, which leaded to a new Earth dynamics cycle.The pattern of upwarping and downwarping structure among different structure systems or different structure blocks , and the characters of different trends and different scale transform structure belts, reflects the structure movement way and their conversion law, and reveals the Earth centralized dynamics mechanics that is produced by the revolutionary effect under the environments of aster system. This can be clearly reflected by the change of impetus way between Qinghai—Tibet highland structure system and near structure system.

Characteristics of the Deep Crustal Structure of the Greenland–Iceland–Faroe Ridge in the North Atlantic

The Greenland–Iceland–Faroe Ridge,located between the central eastern part of Greenland and the northwestern edge of Europe,spans across the North Atlantic.As the core component of the Greenland–Iceland–Faroe Ridge,the Iceland is an alkaline basalt area,which belongs to the periodic submarine magmatism and submarine volcano eruption resulting from mantle plume upwelling(Jiang et al.,2020).For the oceanic plateaus,the characteristics of the Iceland are closest to the continental crust,so the Iceland is considered the most suitable for simulating the earliest continental crust on the Earth(Reimink et al.,2014).